1. Field of the Invention
This invention concerns musical instruments and more particularly wind instruments of the type using a cup mouthpiece and convoluted, generally cylindrical or slightly tapering tubing terminating in a flared end or "bell." This type of instrument is commonly referred to as a "brass" instrument even though often constructed of other bright metals such as silver, nickel, etc.
2. Description of the State of the Art
In brass instruments, resonance of the air column occurs at various pitches of sounds produced by the musician's lips at the mouthpiece. Resonance is caused by the bell of the instrument. Resonance assists the musician in obtaining the tone he desires and also acts to amplify the sound the musician's lips generate at the mouthpiece. The pitches at which resonances will occur depend on the length of the tube defining the "air column" or the path along which the sound travels through the instrument. The tubing length is sufficiently long as to require forming the tubing in loops, as is done in the trumpet, French horn, tuba, and other brass instruments.
In addition, three valves are used to allow the musician to selectively vary the length of the tubing in order to enable resonances to be achieved for each note of a complete musical scale. Each valve is received in one of a bank of valve casings located along the length of the main tubing. The valves allow one of respective U-shaped slide tubes of different lengths to be placed in communication with the tubing defining the air column of the instrument, to in effect vary the length of the air column, shifting the pitches at which resonances will occur.
Resonance necessarily involves a reflection of sound at the bell back into the instrument, but reflection at other points in the bore of the tube is known to cause degeneration of tone. These unwanted reflections may be caused by irregularities along the tube.
Brass instruments act as "coupling" devices which amplify the tones produced by the musician's lips, and this amplification is at its greatest efficiency at the resonant frequencies. Coupling efficiency affects instrument responsiveness (the ease in which the instrument produces a desired tone in response to the efforts of the musician).
It has heretofore been recognized that factors which reduce coupling efficiencies include the incidence of "sympathetic" vibrations, i.e., mechanical vibration of the instrument parts.
It is the object of the present invention to improve the responsiveness and tone of cup mouthpiece or "brass" instruments by minimizing sympathetic vibrations.